Circularly polarized wave reception antenna

ABSTRACT

A GPS loop antenna attached to the front windshield of a vehicle to receive a circularly polarized wave which is improved in reception performance, that is, a loop antenna comprised of a loop-shaped antenna conductor receiving a circularly polarized wave, feed terminals connected to the two ends of the antenna conductor, and a parasitic element positioned near the antenna conductor and made of a conductor independent of the antenna conductor, all arranged on a sheet-like transparent film, wherein a looping line conductor is arranged around the loop antenna on the film. It is sufficient if the total length of the line conductor is about three times the antenna conductor.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Phase Patent Application and claims thepriority of International Application Number PCT/JP2008/069395, filed onOct. 21, 2008, which claims priority of Japanese Patent ApplicationNumber 2007-290036, filed on Nov. 7, 2007.

TECHNICAL FIELD

The present invention relates to a circularly polarized wave receptionantenna. The present invention particularly relates to an improvement ofthe gain of a loop antenna used attached to a dielectric body portion ofan automobile or other vehicle and receiving circularly polarized waves.

BACKGROUND ART

In the past, automobiles and other vehicles have been equipped withantennas enabling the reception of radio waves even during movement.Generally, the radio waves received by a vehicle have for long yearsprincipally been the medium waves (MW) for AM radio and the very highfrequency (VHF) or ultrahigh frequency (UHF) waves for FM radio ortelevision.

However, in recent years, the types of antennas mounted at vehicles havebeen increasing. For example, antennas for global positioning systems(GPS) or antennas for receiving radio waves for digital terrestrialbroadcasts have been increasingly becoming mainstream. Antennasreceiving radio waves for digital terrestrial TV broadcasts hereinafterwill be referred to as “DTV antennas”.

Circularly polarized waves have been used for the GPS radio waves orterrestrial digital TV broadcast radio waves received by such antennasmounted on vehicles. Further, for conventional circularly polarized waveantennas, patch antennas have usually been used. However, such a patchantenna is contained inside an antenna case. The case is tall andtherefore the appearance was bad. Therefore, recently, film antennasused attached to the windows of the vehicles have been used (forexample, see Japanese Patent Publication (A) No. 2005-102183).

However, the film antennas disclosed in Japanese Patent Publication (A)No. 2005-102183 etc. were not sufficient in reception performance.

DISCLOSURE OF THE INVENTION

Therefore, the present invention has as its object to provide acircularly polarized wave reception antenna able to be increased ingain, able to be improved in reception performance, and able to providesufficient performance even as a film antenna.

A circularly polarized wave reception antenna of the present inventionfor achieving this object comprises a loop antenna provided with twofeed terminals, a parasitic element positioned near the loop antenna andcomprised from a conductor independent of the antenna conductor of theloop antenna, and a conductor positioned so as to surround the vicinityof the loop antenna and parasitic element. This conductor can be made alooping line conductor.

According to the antenna of the present invention, there is provided anantenna with a simple structure and good reception performance able tosend and/or receive circularly polarized waves.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view showing the structure of a circularly polarizedwave reception antenna of a first embodiment of the present invention.

FIG. 1B is a perspective view showing an example of installation of theantenna shown in FIG. 1A at the front window of an automobile.

FIG. 2 is a plan view showing the structure of a circularly polarizedwave reception antenna of a second embodiment of the present invention.

FIG. 3A is a view showing a modification of a circularly polarized wavereception antenna of the first embodiment shown in FIG. 1A wherein alooping line conductor with an exterior rectangular shape has a lateraldirection length X much longer than a longitudinal direction length Y.

FIG. 3B is a view showing a modification of a circularly polarized wavereception antenna of the first embodiment shown in FIG. 1A wherein alooping line conductor with an exterior rectangular shape has a lateraldirection length X slightly longer than a longitudinal direction lengthY.

FIG. 3C is a view showing a modification of a circularly polarized wavereception antenna of the first embodiment shown in FIG. 1A wherein alooping line conductor with an exterior rectangular shape has a lateraldirection length X nearly equal to a longitudinal direction length Y.

FIG. 3D is a view showing a modification of a circularly polarized wavereception antenna of the first embodiment shown in FIG. 1A wherein alooping line conductor with an exterior rectangular shape has a lateraldirection length X slightly shorter than a longitudinal direction lengthY.

FIG. 3E is a view showing a modification of a circularly polarized wavereception antenna of the first embodiment shown in FIG. 1A wherein alooping line conductor with an exterior rectangular shape has a lateraldirection length X much shorter than a longitudinal direction length Y.

FIG. 4A is a perspective view showing the appearance of a connector andcoaxial cable connected to a feed terminal of a loop antenna.

FIG. 4B is a disassembled perspective view of the connector shown inFIG. 4A.

FIG. 5A is a view of an example of the circuit board shown in FIG. 4Bseen from the bottom surface.

FIG. 5B is a block circuit diagram showing the internal structure of anamplifier mounted on the circuit board shown in FIG. 5A.

FIG. 5C is a view of another example of a circuit board shown in FIG. 4Bseen from the bottom surface.

FIG. 6A is a plan view showing the structure of a modification of theantenna of the first embodiment of the present invention.

FIG. 6B is a plan view showing the general structure of a DTV receptionantenna.

FIG. 6C is a plan view showing a different structure of a DTV receptionantenna.

FIG. 6D is a perspective view of the front windshield of an automobileto which antennas etc. shown from FIG. 6A to FIG. 6C are attached andthe surroundings of the same seen from the vehicle interior.

FIG. 7 is a circuit diagram showing the connection of the antenna shownin FIG. 6D to a navigation system mounted in a vehicle.

FIG. 8A is a plan view showing the structure of a circularly polarizedwave reception antenna of a third embodiment of the present invention.

FIG. 8B is a plan view showing the structure of a modification of theantenna of the third embodiment of the present invention.

FIG. 9A is a perspective view showing an example of use attaching theantenna of the first embodiment of the present invention on the backmirror of an automobile.

FIG. 9B is a perspective view showing an example of use burying theantenna of the first embodiment of the present invention in the backmirror of an automobile.

FIG. 10A is a perspective view showing an example of use incorporatingthe antenna of the present invention inside the rear spoiler of anautomobile.

FIG. 10B is a lateral view showing an example of use incorporating theantenna of the present invention in the rear spoiler of an automobile.

FIG. 11 is a directivity diagram comparing the gain when setting theantenna of the present invention near the top end of the frontwindshield of an automobile to when using a conventional antenna.

BEST MODE FOR CARRYING OUT THE INVENTION

Below, drawings will be used to explain preferred embodiments of thepresent invention. The same component parts will be explained assignedthe same reference notations. Note that, in general, an antenna bothsends and receives radio waves. However, in the embodiments below, tofacilitate understanding, only the case where the antenna receives radiowaves will be explained. The explanation for the case where the antennasends radio waves will be omitted. Needless to say, the transmission ofradio waves from the antenna is included in the present inventionhowever.

FIG. 1A shows the structure of a GPS antenna 13 of a first embodiment ofthe present invention. The GPS antenna 13 of this embodiment is a loopantenna comprised of a sheet-like transparent film 14 on which arectangular antenna conductor 15 and a parasitic element 16 notelectrically connected to the antenna conductor 15 are formed. Theantenna 13 can receive a circularly polarized wave from a GPS satelliteand can send a circularly polarized wave. On the other hand, there arefeed terminals 17, 18 at the two ends of the antenna conductor 15. Laterexplained connectors are connected to these feed terminals 17 and 18.The antenna conductor 15, parasitic element 16, and feed terminals 17and 18 are formed by conductive ink or copper foil or another conductoron the sheet-like transparent film 14.

The GPS antenna 13 of this embodiment has a rectangular looping lineconductor 19 around the antenna conductor 15, parasitic element 16, andfeed terminals 17, 18. The looping line conductor 19 is also formed byconductive ink or copper foil or another conductor on the sheet-liketransparent film 14. The dimensions when arranging this GPS antenna 13on a glass-like dielectric body are as follows for example. The length Zof one side of the rectangular antenna conductor 15 is 30 mm or so, thelength of the distant part P of the parasitic element 16 is 40 mm or so,and the length of the parallel part Q is 20 mm or so.

Further, the length X of the looping line conductor 19 in the lateraldirection can be made 90 mm or so, and the length Y of the looping lineconductor 19 in the longitudinal direction can be made 90 mm or so. Thetotal length of the looping line conductor 19 in this case is 180 mm orso. The aspect ratio can be changed according to the size of the loopantenna inside. Further, the optimum length of the looping lineconductor 19 and the size of the GPS antenna 13 are determined by thedielectric constant of the dielectric body that the GPS antenna 13 isattached to.

Further, if setting the GPS antenna 13 on plastic foam, it is sufficientif the length Z of one side of the loop of the GPS antenna 13 is 50 mmor so, the length of the distant part P of the parasitic element 16 is60 mm or so, and the length of the parallel part Q is 30 mm or so.

If arranging the rectangular looping line conductor 19 around theantenna conductor 15, parasitic element 16, and feed terminals 17, 18,making the total length (2X+2Y) of the looping line conductor 19 aboutthree times (about 2.7 to 3.3 times) the total length (4Z) of theantenna conductor 15 will increase the gain of the GPS antenna 13.Further, the ratio (X:Y) of the length X of the lateral direction of thelooping line conductor 19 to the length Y of the longitudinal directionis optimally 1:1, but there will be improved gain also with a range of1:2 to 2:1.

The GPS antenna 13 with the above such structure can be set near the topend of the front windshield 1 of the automobile 60 as shown in FIG. 1Bfor example. Depiction of the transparent film is omitted in thisdrawing. The GPS antenna 13 is connected to a feed circuit comprising aconnector 20 and coaxial cable 22. The coaxial cable 22 is positionedalong an A pillar 3 of the automobile 60 and is connected to a digitalTV tuner not shown in the drawing. 8 is a car navigation systeminstalled in an instrument panel 9 of the automobile. This receives animage signal from the tuner as input.

As explained above, by setting a GPS antenna 13 comprised of an antennaconductor 15, parasitic element 16, and feed terminals 17, 18 surroundedby a rectangular and looping line conductor 19 near the top end of thefront windshield 1 of the automobile 60, as shown in FIG. 11, there willbe an effect of an increase in gain of approximately 2 dB in comparisonto a case with no looping line conductor 19.

FIG. 2 shows the structure of a GPS antenna 13 of a second embodiment ofthe present invention. The GPS antenna 13 of this embodiment also uses aloop antenna comprised of a sheet-like transparent film 14 on which arectangular antenna conductor 15 and a parasitic element 16 notelectrically connected to the antenna conductor 15 are formed. There arefeed terminals 17, 18 on the two ends of the antenna conductor 15.Connectors are connected to these feed terminals 17, 18. This is thesame as in the first embodiment.

In the first embodiment, the antenna conductor 15, parasitic element 16,and feed terminals 17, 18 were surrounded by the rectangular loopingline conductor 19. On the other hand, in the second embodiment, theantenna conductor 15, parasitic element 16, and feed terminals 17, 18are surrounded by a vertically long elliptical looping line conductor19. Here as well, making the total length of the looping line conductor19 three times or so the total length (4Z) of the antenna conductor 15will increase the gain of the GPS antenna 13. Further, in this case, theratio (X:Y) of the length X of the minor axis of the elliptical lineconductor 19 to the length Y of major axis is optimally 1:1, but thereis an effect of raising the gain even in a range of 1:2 to 2:1.

Note that, the antenna 13 of the first embodiment, as shown in FIG. 3C,preferably has a ratio (X:Y) of the length X of the lateral direction ofthe looping line conductor 19 to the length Y of the longitudinaldirection of 1:1 or so. However, even if changing the X:Y ratio, withoutchanging the sum of the side X and side Y, by making the length of theside X longer and conversely making the length of the side Y shorter soas to obtain the antenna 13 in the state shown in FIG. 3B, the gain isgreater than in an antenna 13 of a state without a looping lineconductor 19. Similarly, even if changing the ratio of X:Y, withoutchanging the sum of the side X and side Y, by making the length of theside X even longer and making the length of the side Y even shorter soas to obtain the antenna 13 (X:Y=2:1) in the state shown in FIG. 3A, thegain is greater than in an antenna 13 of a state without a looping lineconductor 19. Further, even if changing the X:Y ratio, without changingthe sum of the side X and side Y, by making the length of the side Xshorter and making the length of the side Y longer so as to obtain theantenna 13 in the state shown in FIG. 3D or FIG. 3E, the gain is greaterthan in an antenna 13 of a state without a looping line conductor 19.Further, if making the X:Y ratio 1:2 like the antenna 13 in the stateshown in FIG. 3E, the gain will be no different from the antenna 13shown in FIG. 3A.

FIGS. 4A and 4B show the appearance of the connector 20 shown in FIG. 1Band the connector 20 in a disassembled state. As shown in FIG. 4A, theconnector 20 comprises a combination of an inner case 21 and outer case25. The surface of the inner case 21 (the surface the antenna 10 ismounted to) has two openings 21A, 21B. Connection terminals 31, 32having springiness protrude from these openings 21A, 21B. The connector20 is fixed on top of each of the feed terminals 17, 18 with two-sidedadhesive tape or other adhesive stuck on the surface of the inner case21.

The connection terminals 31, 32, as shown in FIG. 4B, are mounted on onesurface of the circuit board (dielectric board) 30 built in the innercase 21 and outer case 25. The circuit board 30 is connected to acoaxial cable 22. The other surface of the circuit board 30 is equippedwith an integrated circuit 40 to be mentioned later. Generally, theconnection terminal 31 is the hot side (signal transmission side)terminal, and the connection terminal 32 is the ground side terminal.

FIG. 5A shows the general structure of the circuit board 30 inside theconnector 20 shown in FIG. 4B excluding the inner case 21 and outer case25. Connection terminals 31, 32 are mounted on the bottom surface sideof the circuit board 30 and are led to the top surface side of thecircuit board 30 by the through holes 33, 34. In this example, thethrough hole 33 is connected to the input terminal of the integratedcircuit 40 mounted on the top surface of the circuit board 30, and thethrough hole 34 is connected to the ground line (outside conductor) 22Bof the coaxial cable 22. The integrated circuit 40 amplifies andotherwise processes the signals received by the antennas and outputs theprocessed signals to a center conductor (inner side conductor) 22A ofthe coaxial cable 22.

FIG. 5B shows the internal structure of the integrated circuit 40 shownin FIG. 5A. The integrated circuit 40 has inside it a filter 41connected to the antenna 10, an amplifier 42 amplifying a signal outputfrom the filter 41, and a filter 43 determining the signal band outputfrom the amplifier 42. This filter 43 is connected to the centerconductor 22A of the coaxial cable 22 through a capacitor 44 whichblocks direct current. This coaxial cable 22 is a cable also supplyingpower. The power voltage (direct current) is supplied to the amplifier42 through the coil 45 blocking the alternate current component.

FIG. 5C shows the structure of a circuit board 30 different from theconnector 20 shown in FIG. 5A excluding the inner case 21 and outer case25. In the circuit board 30 of the connector 20 shown in FIG. 5A, theconnection terminal 31 is the hot side (signal transmission side)terminal which is connected to the input terminal of the integratedcircuit 40 through the through hole 33, and the connection terminal 32is the ground side terminal which is connected to the ground line 22B ofthe coaxial cable 22 through the through hole 34. On the other hand, inthe circuit board 30 of the connector 20 shown in FIG. 5C, theconnection terminal 31 is the ground side terminal and is connected tothe ground line 22B of the coaxial cable 22 through the through hole 34,and the connection terminal 32 is the hot side terminal and is connectedto the input terminal of the integrated circuit 40 through the throughhole 33. In this way, the connection terminal 31 may also be made theground side terminal and the connection terminal 32 the hot sideterminal.

In the first embodiment, it was found by experiments that therectangular looping line conductor 19 surrounding the antenna conductor15, parasitic element 16, and feed terminals 17, 18 is effective even ifthe conductor is not continuous across the entire circumference.Further, it was found that the rectangular looping line conductor 19surrounding the feed terminals 17, 18 of the GPS antenna 13 had a totallength close to the loop length of the loop antenna that the DTV antennais comprised from. Thus, the inventors proposed cutting out a portion ofthe rectangular looping line conductor 19, forming the feed terminals11, 12 at the cut-out ends shown in FIG. 6A, and making the rectangularlooping line conductor 19 a DTV antenna 10A.

In this case, an integrated antenna 10A, 13 in which the GPS antenna 13and DTV antenna 10A are combined as shown in FIG. 6A is positioned atthe top left corner of the front windshield 1 of the automobile 60. Inaddition, the DTV antenna 10D shown in FIG. 6B, the DTV antenna (withfeed terminals 11, 12 offset to one side) 10B shown in FIG. 10C, and theDTV antenna 10C which is a mirror image of the DTV antenna 10D shown inFIG. 10C can be arranged in a line from the integrated antenna 10A, 13on the top end of the front windshield 1 of the automobile 60 as shownin FIG. 6D to form an antenna system. Note that, in the antenna systemshown in FIG. 6D, the feed terminals of the antennas are connected toconnectors so depiction of the feed circuits comprised of the connectorsand coaxial cables is omitted.

FIG. 7 is a circuit diagram showing the connection of the antenna systemcomprised of the antennas 10A, 13, 10B, 10C, 10D of FIG. 6D to thenavigation system 8 mounted in a vehicle. In this embodiment, there is abuilt-in TV tuner 5 in the navigation system 8, however, the TV tuner 5may also be separate from the navigation system 8.

In this embodiment, the antenna conductor 19 in the integrated antenna10A, 13 and the film antennas 10B, 10C, and 10D are DTV antennas, andthe antenna conductor 15 in the integrated antenna 10A, 13 is a GPSantenna. The DTV signals received by these film antennas 10A, 10B, 10C,and 10D are guided to the TV tuner 5 with cables 22 through integratedcircuits 40 that are built inside the connectors and performamplification and the like. A demodulated image is displayed in thedisplay 6 when the navigation system 8 is in the TV mode. Further, theGPS signals received by the GPS antenna 13 (antenna conductor 15)mounted in the film antenna 10AM are guided through an integratedcircuit 40 and cable 22 to the ECU 4 of the navigation system 8 wherethe current location of the automobile is detected and displayed on thedisplay 6 of the navigation system 8 together with map information.

FIG. 8A shows the structure of the antenna 53 of a third embodiment ofthe present invention. The GPS antenna 13 of the third embodiment alsouses a loop antenna comprised of a sheet-like transparent film 14 onwhich a rectangular antenna conductor 15 and a parasitic element 16 notelectrically connected to the antenna conductor 15 are formed. It canreceive a circularly polarized wave from a GPS satellite and, further,send a circularly polarized wave. On the other hand, there are feedterminals 17, 18 at the two ends of the antenna conductor 15. Laterexplained connectors are connected to these feed terminals 17, 18. Theantenna conductor 15, parasitic element 16, and feed terminals 17, 18are formed by conductive ink or copper foil or another conductor on asheet-like transparent film 14 in the same way as the first embodiment.

In the GPS antenna 53 of the third embodiment, a metal sheet 51 havingan opening of the same dimensions as the rectangular looping lineconductor 19 explained by the first embodiment is attached on thetransparent film 14 around the antenna conductor 15, parasitic element16, and feed terminals 17, 18. In the third embodiment, so long as thedimensions of the opening of the metal sheet 51 are the same, the sizeof the metal sheet 51 is not particularly limited. For example, when thelength Z of one side of the rectangular antenna conductor 15 of the GPSantenna 13 is 32 mm or so, the length of the lateral direction of theopening of the metal plate 51 may be 95 mm or so and the length of thelongitudinal direction 95 mm or so.

FIG. 8B shows a modification of the antenna 53 of the third embodimentof the present invention. The only difference between the antenna 53 ofthis modification and the antenna 53 of the third embodiment explainedin FIG. 8A is that instead of the metal sheet 51, a metal mesh 52 isattached to the sheet-like transparent film 14. The performance of theantenna 53 of this modification is not much different from that of theantenna 53 of the third embodiment.

FIG. 9A shows an example of usee where the antenna 13, 53 of the firstor third embodiment of the present invention is attached to the backmirror (inner rearview mirror 35) of an automobile. Further, FIG. 9Bshows an example of use where the antenna 13, 53 of the first or thirdembodiment of the present invention is buried in the back mirror 35 ofthe automobile. By mounting the antenna 13, 53 of the present inventionat this position, it can efficiently receive radio waves arriving fromthe upper front of the automobile.

FIGS. 10A and 10B show, as different examples of vehicle positions tomount the antenna 13, 53 of the present invention, examples where theantenna 13, 53 is built inside the rear spoiler 36 of a wagon typeautomobile 37. The directivity of the antenna 13, 53 at this positioncan be changed by the mounting angle of the antenna 13, 53 built insidethe rear spoiler 36. As shown in FIG. 10A, by having the antenna 13, 53built into the rear spoiler 37 tilted to the back direction, thedirectivity of the antennas 13, 53 is to the upper rear of theautomobile 37. Further, as shown in FIG. 10B, by having the antenna 13,53 built into the rear spoiler 36 tilted to the front, the directivityof the antennas 13, 53 is to the upper front of the automobile 37.

The antennas 13, 53 of the present invention can be mounted at positionsother than these mounting positions, for example, a plastic rooftop etc.of the vehicle. The shape of the antenna conductor of the GPS antenna 13that can be used in the antennas 13, 53 of the present invention and thenumbers and arrangements of the parasitic elements 16 are not limited tothese embodiments.

The invention claimed is:
 1. A circularly polarized wave receptionantenna comprising: a loop antenna having two feed terminals; aparasitic element positioned near and outside the loop antenna andcomprised of a conductor independent of an antenna conductor of the loopantenna; and a closed loop conductor having no feed terminal positionedto surround a vicinity of the loop antenna and the parasitic element,and positioned to increase a gain of the loop antenna having the twofeed terminals, wherein the loop antenna, the parasitic element, and theclosed loop conductor are formed in a same plane, and wherein the totalcircumference of the closed loop conductor is 2.7 to 3.3 times the totalcircumference of the loop antenna, the closed loop conductor isrectangular, and a ratio of two adjacent sides of the rectangular closedloop conductor is in a range of 1:2 to 2:1.
 2. The antenna as set forthin claim 1, wherein the closed loop conductor is a line loop conductor.3. The antenna as set forth in claim 1, wherein the closed loopconductor is a metal sheet, and the loop antenna and the parasiticelement are positioned inside an opening in the metal sheet.
 4. Theantenna as set forth in claim 1, wherein the loop antenna, the parasiticelement, and the closed loop conductor are formed on top of a sheet-likedielectric body.
 5. The antenna as set forth in claim 4, wherein thesheet-like dielectric body is a transparent film.
 6. The antenna as setforth in claim 1, wherein the parasitic element includes a parallel partparallel to the loop antenna and a distant element distant from the loopantenna, and the closed loop conductor includes a part parallel to thedistant element.
 7. A circularly polarized wave reception antennacomprising: a loop antenna having two feed terminals; a parasiticelement positioned near and outside the loop antenna and comprised of aconductor independent of an antenna conductor of the loop antenna; and aclosed loop conductor having no feed terminal positioned to surround avicinity of the loop antenna and the parasitic element, and positionedto increase a gain of the loop antenna having the two feed terminals,wherein the loop antenna, the parasitic element, and the closed loopconductor are formed in a same plane, and wherein the totalcircumference of the closed loop conductor is 2.7 to 3.3 times the totalcircumference of the loop antenna, the closed loop conductor is anellipse, and a ratio of a major axis and a minor axis of the ellipse isin a range of 1:1 to 2:1.
 8. The antenna as set forth in claim 7,wherein the closed loop conductor is a line loop conductor.
 9. Theantenna as set forth in claim 7, wherein the closed loop conductor is ametal sheet, and the loop antenna and the parasitic element arepositioned inside an opening in the metal sheet.
 10. The antenna as setforth in claim 7, wherein the loop antenna, the parasitic element, andthe closed loop conductor are formed on top of a sheet-like dielectricbody.
 11. The antenna as set forth in claim 10, wherein the sheet-likedielectric body is a transparent film.
 12. The antenna as set forth inclaim 1, wherein the loop antenna, the parasitic element, and the closedloop conductor are formed on top of a transparent film, and thetransparent film is attached to a top end of a front window of anautomobile.
 13. The antenna as set forth in claim 1, wherein the loopantenna, the parasitic element, and the closed loop conductor are formedon top of a sheet-like dielectric body, and the dielectric body isattached to a surface opposite to a mirror of a back mirror of anautomobile.
 14. The antenna as set forth in claim 1, wherein the loopantenna, the parasitic element, and the closed loop conductor areembedded in a surface opposite to a mirror of a back mirror of anautomobile.
 15. The antenna as set forth in claim 1, wherein the loopantenna, the parasitic element, and the closed loop conductor areembedded in a rear spoiler of an automobile.
 16. The antenna as setforth in claim 7, wherein the loop antenna, the parasitic element, andthe closed loop conductor are formed on top of a transparent film, andthe transparent film is attached to a top end of a front window of anautomobile.
 17. The antenna as set forth in claim 7, wherein the loopantenna, the parasitic element, and the closed loop conductor are fowledon top of a sheet-like dielectric body, and the dielectric body isattached to a surface opposite to a mirror of a back mirror of anautomobile.
 18. The antenna as set forth in claim 7, wherein the loopantenna, the parasitic element, and the closed loop conductor areembedded in a surface opposite to a mirror of a back mirror of anautomobile.
 19. The antenna as set forth in claim 7, wherein the loopantenna, the parasitic element, and the closed loop conductor areembedded in a rear spoiler of an automobile.